Composite air dome structure



N. R. sEAMAN Oct. 9,

In ICI.

Diallo FIG. A2

ATTORNEYS N. R. SEAMAN COMPOSITE AIR DOME STRUCTURE Oct. 9, 1962 2Sheets-Sheet 2 Filed May 5, 1960 FIG. 8

INVENTOR. R

NORMAN EAMAN BY ATTORNEYS A3,057,368 Patented Oct. 9, 1962 hee 3,657,368CMPSTE Am DOME STRUCTURE Norman R. Seaman, RD. 1, Holmesvlle, Ohio FiledMay 3, 1960, Ser. No. 26,615 8 Claims. (Cl. 13S-1) The invention relatesgenerally to inatable bag-like structures which are continuouslymaintained in a blownup condition on a supporting surface by a blower orthe like. More particularly, the invention relates to an inated outerbag or dome wholly enclosing a frame-supported, air-sealed structure.

Inflated bag-like structures are usually made of plastic film materialand may be called air domes. They have the advantages of being made andtransported economically, and of providing a shelter which is quicklyand easily erected or collapsed and which greatly `reduces the designloads for wind resistance because of their spherical or dome shape.However, these air domes have a number of disadvantages, including thefollowing:

rl'he plastic film material is subject to rupture from a variety ofcauses resulting in accidental collapse of the structure. Specialair-lock type doors are required for ingress and egress to prevent lossof air. A constantly running blower of substantial capacity is requiredto compensate for air losses through the doors and ground seals, andthis causes an undesirable draft condition for the occupants. These airlosses and the lack of thermal insulation make it difficult andexpensive to heat and maintain the temperature of the air within thedome.

Other tent-like structures having a framework supporting film materialhave been proposed, and these do not require air inflation `but have anumber of other disadvantages. For example, a geodesic structure such asdisclosed in U.S. Patent No. 2,682,235 provides a lightweight frameworkhaving relatively low design loads which may be used to support the filmor skin, but it must be designed for the most severe uneven loadings dueto wind and snow conditions. Moreover, scaffolding or structural riggingis required to erect the framework. Also, because the skin must bedesigned for point loading where it is attached to the framework, thepatterning and construction of the skin is a difficult and relativelyexpensive operation.

Another disadvantage of using a geodesic framework to support the skinis that it is necessary to support the skin from the inside of theframework to make it waterproof because of the difficulty of lifting theheavy whole skin over the outside of the framework and the danger ofwind damage during the erection. Thermally insulating such a skin is acomplicated and expensive task, usually requiring two spaced-apartwaterproof skins to provide a dead air space.

It is a general object of the present invention to provide a novel andimproved composite air dome structure which overcomes the disadvantagesof both air domes and framesupported skins, while retaining theprincipal advantages of both.

More specifically, it is an object to provide a novel composite domestructure having an outer dome which is quickly and easily erected byinflation, which will efliciently resist the severest wind and snowloads, and which provides an overhead support for erecting a separatestructure enclosed within the dome, regardless of weather conditions.

Another object is to provide a novel composite dome structure having aninner framework-supported skin and an outer inflated skin normallysupported solely by air pressure between the skins, so that air atatmospheric pressure may be maintained within the inner skin, anddoorways extending through the space between the skins do not requireair locks.

A further object is to provide a novel composite dome structure havingan inner chamber thermally insulated by an air blanket from the outeratmosphere while permitting the transmission of a substantial amount ofdaylight into the inner chamber.

Referring to the drawings forming part hereof:

lFIG. l is a somewhat schematic vertical sectional view on line 1-1 ofFIG. 2 of the novel composite air dome structure in inflated condition,showing the manner of hoisting the inner framework from the central partof the outer dome.

FIG. 2 is a plan view, with parts of the outer and inner skins brokenaway.

FIG. 3 is an enlarged fragmentary view on line 3-3 of FIG. 2 showing thebase of the inner framework with the inner skin supported on the insideof the framework.

FIG. 4 is a similar View of a modified construction, showing the innerskin supported on the outside of the framework.

FIG. 5 is an enlarged fragmentary View on line 5-5 of FIG. 2 of thecentral portion of the outer dome, showing a lifting ring secured to itsinner surface.

FIG. 6 is an enlarged fragmentary View taken within the circle on FlG.1, showing the manner of supporting the skin on the inside of the innerframework.

tFlG. 7 is a schematic vertical sectional view through a doorway leadinginto the inner chamber.

FIG. 8 is a view similar to FIG. 1, showing a modified form of innerframework supporting an outside skin.

The outer skin or film 10 may be made of any exible transparent ortranslucent plastic material such as polyethylene or polyvinyl chloride,and may comprise a plurality of spherical sections 11 joined together byfluidtight seams along the gore lines 12. Preferably, the seams areelectronically Welded. As indicated in FIG. 1, the skin 10 has an inletport 13 to which a blower 14 is connected for supplying and maintainingair under pressure within the outer skin which is designed to assume ahemispherical or dome shape when inated and supported on the ground orother support.

The inner framework may be a geodesic structure, indicated generally at15, such as shown and described in U.S. Patent No. 2,682,235, comprisinga plurality of struts 16 forming substantially equilateral trianglesarranged to form a partial dome in spaced relation to the outer skin andconnected at its base to the base of the outer skin. The struts areconnected to each other by suitable couplings 17 described in saidpatent, and the framework is provided with a circular ring 18 at itsbase.

Referring to FIG. 3, the base ring 18 of the framework may be supportedat suitable circumferential intervals (e.g. l0 feet) by steel structuralmembers indicated at 20, each resting on a pad or foundation 21. Theouter skin 1i) is attached to the base ring between struts 16 by loops22 of the skin material. Overlying the loops 22 is an outercircumferential flap or skirt 23 of the skin material which extendsradially inward under the base ring around its entire circumferenceexcept for doors. Where'the skirt is interrupted to pass the structuralsupports 20, ground flaps 24 are provided to make an air seal around thesupports. All of the seams in the loops 22, skirt 23 and flaps 24 areelectronically welded or otherwise sealed to make them airtight.

As shown in FIG. 3, the skirt 23 may have its radially inner portionoverlap and be laced by a iiap 25 to an inner skin 26, which may be hungfrom the inside of the geodesic framework at some or all of thecouplings 17 connecting the struts 16. The skin 26 may be of the samematerial as the outer skin or it may be a different material havingsomewhat different characteristics such as a high thermal insulationfactor.

As seen in FIG. 6, each coupling 17 has an eye bolt 27 extending fromits inner end, and the skin 26 may be supported therefrom by a chain 28which is attached to an eye bolt 29 at the center of a metal doublewalldisk 30 clamped around its periphery over a circular hem in the skinenclosing a cord or rope 31 to make an airtight seal. The inner skin 26divides the hemispherical chamber dened by the outer skin into twochambers, the upper chamber being substantially crescent-shaped in crossSection, as indicated in FIG. 1, and containing the air maintained underpressure by the blower 14. The lower chamber contains atmospheric airwhen the strueture is completed.

When the inner skin is supported on the top or outside of the geodesicframework, as shown in FIG. 4, the inner and outer skins 126 and 110 maybe connected to form a seal above the loops 122 surrounding the basering 118. The outer edge of skin 126 may be laced to a flap 132 weldedto the inside of skin 110, and a sealing ap 133 overlies the laced jointand is welded to both skins. In

this case the outer skirt 123 may extend under the base ring duringerection as indicated in full lines, and may be subsequently extendedoutwardly to form a weather seal ground flap, as indicated in dashlines.

As shown in phantom lines in FIG. 4, in order to provide working spacebetween the inner structure and outer skin, the outer skin 110 may havea separate anchored base ring 118 spaced outwardly of the base ring 118.A flap 133' would then be provided to connect the outer skin 110 to theinner skin 126, which lwould be attached to the inner ring 118 by loops122'.

A-s shown in FIG. 7, it is not necessary to construct special air-lockdoors to allow ingress to and egress from the lower chamber. The doorframes 35 are merely formed where desired in the base of the framework15, and the inner and outer skins and 26 are sealed together andsupported by the top 36 of the door frame, either below or above thesame.

In erecting the novel composite air dome, the outer skin 10 is firsterected at the desired location merely by introducing air therein fromthe blower 14. The skirt 23 extends radially inward around the outerperiphery of the skin to provide a fairly good air seal with the groundor other support. As indicated in FIGS. 1 and 5, the upper portion ofthe outer skin is preferably provided on its inner surface with ahoisting or lifting ring 38 carried in a loop-shaped circular flap 39welded to the skin. Hoisting cables 40 are hung from the ring 38 atintervals.

After the outer skin is fully inflated, the geodesic framework iserected within the outer skin, and consequently the framework can beerected regardless of weather conditions due to the protection affordedby the outer skin. The top portion of the framework is erected on theground irst and then raised progressively by the cables 40 as the lowerportions of the framework are added. When the framework is completed,the base ring is attached to the outer skin by the loops 22 or 122.

Next, the inner skin 26 or 126 is hung from or placed over the frameworkand joined at its outer periphery to the outer skin in the mannerpreviously described. Due to the protection from the elements providedby the outer skin, the inner skin may be applied over the framework insections for ease in handling, and the sections seamed together inplace. After the inner and outer skins are joined together, the air inthe lower chamber is allowed to become atmospheric and the air pressuremaintained in the upper chamber.

As shown in FIG. 8, the inner framework may be of conventional buildingconstruction comprising studs 250 and rafters 251 carrying the innerskin 226 on the framework in spaced relation to the outer skin 210, andthe two skins being sealed together between the framework and the outerskin. The inner skin may be supported on the inside of the framework, oron the outside thereof as shown. Where doors are located, door framesare preferably provided connecting the framework to the base 4 ring andsupporting the joined rskins above the doorway, similar to theconstruction shown in FIG. 7.

In all embodiments, after the inner skin is supported on the innerframework and sealed to the outer skin, the blower is required only tomaintain the desired air pressure in the upper chamber, which iscompletely sealed, so that a blower of relatively small capacity may beused. It has been found in actual practice that air pressures of 71/2 tolll/1 pounds per square foot will maintain the outer skin in placeagainst the severest snow loads and winds of 50 to 75 miles per hour.Even higher velocity winds will merely slightly depress or distort theskin without harm. However, should the outer skin become ruptured forany reason, it will be prevented from total collapse by the innerframework.

Since the inner framework is at all normal times protected by the outerskin, the framework can be designed for uniform reduced loadingconditions, resulting in a substantial savings in material and handlingcosts.

The upper chamber of air thermally insulates the lower and innerchamber, so that maintaining a desired temperature within the innerchamber is greatly facilitated, regardless of outside weatherconditions. If desired, a layer of insulating material, such aspolyurethane foam, can be supported on the inner framework to furtherinsulate the inner chamber.

The novel composite air dome structure is adapted to be used to protectand enclose areas for various purposes. For example, it is adapted tocover Water reservoirs, and can be erected from oats supported upon thesurface of the water. Moreover, it can be erected under almost anyclimatic condition, because the outer skin is erected merely byinilation and provides a protective housing for the erection of theinner framework and skin.

By using transparent or translucent material in both the inner and outerskins, an optimum of natural light can be transmitted to the innerchamber, thereby reducing the amount of articial lighting required.

What is claimed is:

l. Composite air dome structure comprising an outer air-supporteddome-shaped skin, a base ring attached to the base portion of said skin,a geodesic framework carried on said ring within said skin, and an innerilexible skin having a continuous air seal connection with said outerskin base portion and supported on the outer surflce of said frameworkin spaced relation to said outer s. in.

2. Composite air dome structure comprising an outer air-supporteddorne-shaped skin, a base ring attached to the base portion of saidskin, a geodesic framework carried on said ring within said skin, and aninner exible skin having a continuous air seal connection with saidouter skin base portion and supported on the inner surfce of saidframework in spaced relation to said outer s.1n.

3. Composite air dome structure comprising an outer air-supporteddome-shaped skin, means anchoring the base portion of said skin to asupport, a geodesic framework carried on said means within said skin,and an inner flexible skin having a continuous air seal connection withsaid outer skin base portion and supported on the outer surface of saidframework in spaced relation to said outer skin.

4. Composite air vdome structure comprising an outer air-supporteddome-shaped skin, means anchoring the base portion of said skin to asupport, a geodesic framework carried on said means within said skin,and an inner exible skin supported on the inner surface of saidframework in spaced relation to said outer skin and forming a sealed airchamber between said skins.

5. Composite air dome structure comprising an outer air-supported-domeashaped skin, a base ring attached to the base portion of saidskin, a geodesic framework carried on said ring within said skin, aninner flexible skin having a continuous air seal connection with saidouter skin base portion and supported by said framework in spacedlrelation to said outer skin, and an air inlet in said outer skin forintroducing air under pressure between said skins.

6. Composite air dome structure comprising an outer air-supporteddome-shaped skin, means anchoring the base portion of said skin to asupport, a geodesic framework carried on said means within said skin, aninner flexible skin having a continuous air seal connection with saidouter skin base portion and supported by said framework in spacedrelation to said outer skin, and an air inlet in said outer skin forintroducing air under pressure between said skins.

7. Composite air dome structure comprising an outer air-supporteddome-shaped skin, means anchoring the base portion of said outer skin toa support, a circumferential ap extending radially inward of the baseportion of said outer skin, a framework within the outer skin in spacedrelation thereto, and an inner exible skin supported on said framework,the outer periphery of said inner skin having a sealed connection withsaid flap.

8. Composite air dome structure comprising an outer air-supporteddome-shaped skin, a framework within the outer skin in spaced relationthereto and having a base, means anchoring the outer skin to said base,a circumferential flap on said outer skin extending radially inward ofsaid base, and an inner eXible skin supported on said framework andhaving its outer periphery sealed to said ap to form a sealed airchamber between said inner and outer skins.

References Cited in the le of this patent UNITED STATES PATENTS2,411,316 Capita Nov. 19, 1946 2,819,724 Barker Ian. 14, 1958 2,914,074Fuller Nov. 24, 1959 2,934,075 Richardson et al Apr. 16, 1960

